The studies outlined in this proposal include: an examination of the mechanism of foreign antigen recongition by T-lymphocytes (Thomas); the differentiation of neuronal cells from the neural crest and molecular studies of the development of neuronal function (Barald); homonal regulation of cell membrane characteristics in rat hepatoma cells (Gelehrter); a study of the rabbit leukocyte (neutrophil) chemotaxis receptor and cloning of the gene for the receptor (Nairn); and the homonal regulation of Ca++ ion in Sertoli cells of the rat testis as well as the role of calmodulin in the mechanism of regulation of the action and structure of the eukaryotc mitotic apparatus (Welsh). All of these studies would greatly benefit from acquisition of a 'no-flow' cytometer, one that sorts and isolates both adherent and non-adherent cells from monolayers, and which is also capable both of fluorescence measurements of indiidual-labelled cells over time and fluorescene photobleaching with subsequent monitoring of recovery in individual cells of the monolayer. In addition, exciting possibilities for development of new applications of the instrument exist in all of these areas.